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BACKGROUND: The keloid scar is a significant clinical problem with the primary treatment being, post excision intralesional corticosteroid injections. Corticosteroids can be highly efficacious, but there can be a high rate of reoccurrence. It is reported corticosteroids lose their bio-effectiveness through exposure to air, oxidation. Kenalog, is a commonly used corticosteroid injected intralesionally to prevent the reoccurrence of keloids. Commonly a single vial of Kenalog is reused over time; thus allowing corticosteroid oxidation to occur. The objective of this study is to compare oxidized to fresh corticosteroids on cultured keloid fibroblasts viability.
METHODS: Keloid derived cultured fibroblasts were maintained in cell culture under standard growth conditions. Fibroblasts at 15,000 cells per 2.0 cm² well of a 24 well plate were placed in 3 treatment groups: fibroblasts alone; fibroblasts with fresh Kenalog (new unopened vial); and fibroblasts with oxidized Kenalog, the vial exposed to 100% oxygen.
RESULTS: At 7 days the fibroblast alone group had 10,876 + 1400 cells/dish. Cells treated with fresh Kenalog at concentrations 4, 2 and 1 nM had 800 + 200; 900 + 200 and 1100 + 300 cells/dish respectively; Oxidized Kenalog at concentrations 4, 2 and 1 nM had 1400 + 400, 3000 + 400 and 5100 + 600 cells/dish respectively.
CONCLUSIONS: Kenalog suppresses keloid fibroblast viability; the fresh Kenalog is more effective than the oxidized Kenalog. Fresh Kenalog reduces fibroblast numbers. The oxidized Kenalog is less effective at suppressing keloid cell viability compared to fresh Kenalog. The suppression of growth by the oxidized Kenalog is enhanced by increasing the concentration of the oxidized Kenalog. Each sealed bottle of Kenalog comes in benzyl alcohol covered by a nitrogen blanket. When a needle penetrates the seal, nitrogen escapes, which is replaced with oxygen containing air, and the oxidation begins. This in vitro data supports the notion that Kenalog exposed to air via a needle aspiration is less effective at suppressing keloid fibroblast growth compared to fresh Kenalog. These experiments may explain the variability of reported results in corticosteroid therapy in the suppression or resolution of the keloid growth.